Mike replied:

Rob, usually any antenna wil do, as long as possible. Try to get the flag as high as possible to give as much warning as you can. Second hand or non operating will do if you don't have a front mounted one. Generally we found that a flag about 1.5m or longer off the bull bar or 1m off the roof rack gave sufficient warning. Use as bright a colour as you can find, but not blue, as these are hard to see against the sky in the background, orange or red seem to be easiest to see. Happy trails, Mike.

Tony replied:

Why not tie a fishing rod (without reel) to your bull bar and place an orange flag (available from bicycle shops) on the top. Cheaper than buying a dedicated pole and a handy place to carry your rod and maybe catch a yellow belly in some of the rivers outback.

Steve replied:

use a piece/ part of a section of an old golf umbrella and sew it to the top of a 2 metre pole/rod /aeriel from top of bull bar !! Not too big as wind will drag on 'pole'
steve

BC replied:

I have devised a better solution.
Get ya Missus to run about 100m ahead of the car while waving her nickers in her hand - I havent had a head-on for years..works for me..try it.
BC

Jim Searle replied:

KMart bike section. Buy a flag pole and use a bit of duck tape. That's what we used for the Simpson. Used from a roof rack, it gave us about an extra 1.5m.

Fred replied:

I have a suggestion that you should consider. I won a replica pole vault pole that I'm trying to get rid of. This is a genuine replica pole vault that was used by Tattaina !!. Wack this on the front of your vehicle and you will be visible forever. Just a thought :-)